This invention relates to a spindle attachment device that attaches a cutting device used for a machine tool to a spindle head.
In the past, a known example of this kind of device is a device including a device body having an attachment surface detachably attached to an end face of a spindle head and engaging means for engaging the spindle head and the device body by moving the device body in a direction of an axial line of the spindle so as to be able to freely restrict or release rotation of the device body with respect to the spindle head about the axial line thereof, wherein a pull stud is supported on the device body in such a manner as to freely move in an axial direction thereof, wherein when the axial line of the pull stud agrees with the axial line of the spindle, the pull stud is inserted into an axial hole of the spindle and coupled with a drawbar, in which state the device body descends due to its own weight, and wherein in this state, the device body is hung from the spindle head by the pull stud, and the device has transmission means for transmitting rotation of the spindle to the device body in this state (for example, see Japanese Unexamined Patent Publication No. S59-219129).
In this conventional device, when the engagement of the engaging means is released and the device body is rotated, the device body is hung from the spindle head, in which state the posture of the rotation thereof is extremely unstable. Therefore, after the device body is rotated, it is difficult to raise the device body and bring the engaging means into engagement.
In addition, after the engaging means is brought into engagement, the posture of the device body is unstable during rotation, which may necessitate engagement between the spindle head and the device body. In this case, since the posture of the device body is unstable during rotation, it is necessary to arrange a large engagement gap. However, if a large engagement gap is arranged, there is a possibility that a foreign material may enter into the spindle head from the gap.